In 1797, R. Abraham of Kalisk, from the Holy Land, wrote a poignant letter attacking the Tanya. His concern was the explicit nature in which R. Shneur Zalman endeavors to explicate the message of the Besht and Maggid via Lurianic concepts.

R. Shneur Zalman wrote Tanya as a systematic guide. His intention was to uplift the masses and allow them to genuinely connect to the higher chain of mystical literature. However, R. Abraham felt that the great majority of Hasidic constituents had no place on that path. Rather, they were only meant to absorb the simple teachings that were placed before them. He did not trust the Hasidim; he did not think that they had the proper tools to understand the true teachings of the Besht and the Maggid.

R. Abraham of Kalisk’s point of contention, the manner in which R. Shneur Zalman explained the Hasidic doctrine, is exactly what made Tanya provocative and unique. R. Shneur created an organized and intellectual manual for his disciples. His goal was to use kabbalistic language in order to rationally elucidate the teachings of the Besht and Maggid. The Tanya employs an intellectual perspective to Hasidism; for this is precisely the meaning of Habad—Hokhmah (wisdom), Binah (understanding) and Da’at (knowledge). R. Abraham felt that empowering the Hasid himself to understand, rationally, the depths of the teachings takes away from the centrality of the Hasidic leader. The leader of a Hasidic group, referred to as the Zaddik, is not a mere communal head, rather he expresses cosmological and spiritual powers. This is perhaps the greatest innovation of Hasidism. R. Shneur Zalman changed this socio-religious dependence that the Hasid maintained towards the Zaddik, since he no longer had to rely on his faith of the Zaddik. Now, the Hasid had direct access to the esoteric teachings.
R. Shneur Zalman changed the leader/disciple relationship by establishing local guides, students of high intellectual pedigree, who assisted others to understand the meaning of Tanya. This was a further critique of R. Abraham of Kalisk, since Hasidic teachings in his mind were not intellectual teachings that could merely be explained. Rather, the illumination of esoteric Hasidic teachings required charisma. He maintained that they were meant to only be given over by a highly elevated and spiritual person— the Zaddikhimself.

Ben Vago, “Head to Head: Power Struggles in the Creation and Formation of the Habad Movement” Milin Havivin 4 (2010), 136-137.

Rabbi Fabian Schonfeld: I think a rabbi who feels burnt out shouldn’t have been a rabbi in the first place. You have to go into this profession, if you can call it a profession, with a spirit of dedication to Torah, to chinuch, to Klal Yisrael. If you do, you don’t get burnt out. I’ve seen rabbis who are burnt out. They get tired of meetings and with fighting with the congregation, with the shul president. But you have to feel the aish da’as, the fire of Torah, within you—independent of age, independent of circumstances. If you don’t have that, you shouldn’t be a rabbi.

Rabbi Dr. Gilbert Klaperman: We have to examine why a rabbi’s burnt out. Is it because he’s working too hard? Or because the challenge is too much for him? Or because he was never meant to be a rabbi? I had a non-Jewish friend [who was] a minister. He used to speak about his colleagues and say, “He was defrocked. He was unsuited.” There are young men who went into the rabbinate out of commitment, out of desire, but they’re not meant to be rabbis. They get burnt out very quickly, because the rabbinate is a challenging profession. It’s hard work. It’s demanding work. It’s intellectually challenging. The rabbis I see here [around this table] don’t look burnt out to me. Why? Because they were suited to be rabbis.

Fifty Years in the Pulpit: Seven Veteran Rabbis Tell It Like It Was,” Jewish Action 69, No. 1 (Fall 5769/2008), 33.

With the emergence of Reform Judaism early in the nineteenth century…, appeal to the concepts of modernity and progress came to serve as the normative criterion for determining the value of Torah law. In the words of the third plank of the Pittsburgh Platform (1885): “We recognize in the Mosaic legislation a system of training the Jewish people for its mission during its national life in Palestine, and today we accept as binding only its moral laws, and maintain only such ceremonies as elevate and sanctify our lives, but reject all such as are not adapted the views and habits of modern civilization.” This statement of Reform Judaism in the nineteenth century demonstrates that the medieval rabbinic resistance to pursuing matters of human authorship was not unfounded. Subsequent history has shown that the traditional halakhic life is indeed endangered if the diachronic character of the Torah is openly and actively developed without any countervailing force. Concentration on the human authors could and, in this case, did detract from belief in the divine origin of the book. When a scripture comes to be seen as a product of culture, one that comes into existence through a long, variegated historical process, then the unity of the scripture – the simultaneity, self-referentiality, and mutual implication of all its parts – is thrown into doubt. As in the case of the third plank of the Pittsburgh Platform, the result is often a justification for the nonperformance of scriptural norms, in this instance, offensive or inconvenient Torah commandments (mitsvot). R. J. Zwi Werblowsky points out that “Liberal and Reform Judaism once welcomed Biblical criticism precisely [because] they found in criticism a welcome ally in their struggle to get rid of the Law and to substitute for it a purely ethical (and so-called ‘prophetic’) Judaism.” In fairness, however, it must also be noted that the perception of the Torah as an artifact of human culture that, like all others, reflects its own period led the liberals, in turn, to suspect that the totality of its norms could no longer be applied in the vastly different historical situation of modern Western Europe and America. As a contingent product of history, the Torah – or at least its superseded aspects – had to yield to the contingencies of history. To avoid the putative fossilization of the community, liberalism elected to fossilize large parts of the Torah, using historical methods to show that they are a dead letter. The theological liberals could do this only because they had shifted the locus of normativity from the text and the tradition onto the historical process, the dictates of autonomous reason, the conscience of the individual, and the like.

Jon D. Levenson, “The Eighth Principle of Judaism and the Literary Simultaneity of Scripture,” in The Old Testament, the Hebrew Bible, and Historical Criticism: Jews and Christians in Biblical Studies (Louisville: Westminster/John Knox, 1993), 75-76.